A Whale Tale from Red Crag Barnacles
Humpback Whales in the Ancient Seas of Suffolk?
By Dr. Simon Jackson, Collections and Learning Curator, Ipswich Museums
Recently we welcomed Professor Andy Gale from the University of Portsmouth who is studying the diversity of barnacles preserved in the Suffolk rocks laid down at the beginning of the ice age. These fossils could help us to understand these past environments and even the diversity and behaviour of ancient whales – a certain barnacle species may even reveal the presence of humpback whales in the ancient sea around what is now Suffolk.
Firstly though, what are barnacles? Well, barnacles belong to the crustacean family (which also includes lobsters, crabs and krill) and there are more than 1400 species found in oceans throughout much of the world. Barnacles have an amazing ability to stick to the surfaces that they live on, whether it’s the seafloor, the undersides of whales and, of course, ships! They can do this through secreting a quick drying substance that is amongst the most powerful natural glues known1.
Professor Gale is here as part of his wider research documenting and cataloguing British fossil barnacles, but he is particularly interested in our unique collection of Red Crag specimens. These creatures lived about 2.5 million years ago at the beginning of the ice age (Late Pliocene-Early Pleistocene). The rocks and fossils of Suffolk at this time document a rich fauna, as the North Sea extended much further inland – along the shoreline, walrus and seals may have looked out into a sea abounding with molluscs, sea urchins, crabs, sharks and whales, while an ancient albatross species soared overhead.
Professor Gale reaches into the specimen-packed grey box and eagerly pulls out a large, tennis ball-sized, boxlike shell with a large hole in one end – in life this shell would have been filled with a tentacle-armed crustacean, reaching out to capture small food particles drifting by in the ocean.
The largest specimens Professor Gale studies belong to a species of Megabalanus, a type of acorn barnacle which grows to some 7cm high. Today, these species live in intertidal environments and so their occurrence 2.5 million years ago, in these parts of Suffolk, indicates the presence of an ancient rocky shoreline, teeming with life. Their large size would have helped to protect them from predation, though now unfortunately would make them more appealing to prospecting humans wanting to harvest them for food.
Professor Gale continues to excitingly rummage through a box of specimens. Something catches his eye. He stops. He eagerly pulls out a small bag full of brown, shard-like objects – “whale barnacles” he enthusiastically remarks. “This species Coronula bifida, which is now extinct, occurs very rarely in the Red Crag and I’m aware of only 7 specimens, 6 of which we have here” he continues.
Whale barnacles in Ipswich Museum collections. Photograph by Prof Andrew Gale and reproduced by his permission.
Whale barnacles are specialists. They live on the skin of whales, using sharp parts to cut deeply into their skin, so that they can hitch a free ride. As the whale swims and particularly when it feeds, the food particles disturbed by the movement can be caught by the tentacle-like arms (or cirri) of the barnacles. So, they effectively get a free lunch as well.
What’s special about this Red Crag species, is, if it’s anything like its close living relatives today, it probably preferred to hitch a ride on the long-flippered, singing humpback whales (though other whales can also be hosts).
So, it’s possible that some of the numerous bone fragments in the museum collections – ribs, ear bones and other skull fragments, from the Red Crag, may in fact belong to humpback whales. What’s even more remarkable, is that these fossils may be evidence of an ancient migration route or breeding ground – today whale barnacles tend to drop off their giant, unsuspecting hosts at these places.
Today, humpback whales are rarely spotted in the British Isles, tending to occur to the north of Scotland and in the Irish Channel: sightings in the North Sea tend to be to the east of Scotland2. Therefore, are these whale barnacles evidence of an ancient population of humpback whales migrating or breeding along the east coast of Britain?
Previous studies have in fact looked at ancient distributions of whale barnacles (of this Coronula species) to infer whale migratory routes, possibly of humpbacks – in 2009, the distribution record of whale barnacle fossils shed light into one of the oldest cetacean migration routes, in the western Pacific, extending back into the Miocene (11.2 million years ago)3.
However, only through detailed comprehensive studies of fossil whale barnacles, looking at when and where they occur – studies such as the one Professor Gale is undertaking – can such migratory studies be founded. And the Ipswich Museum collections have the potential to unlock the understanding of barnacle diversity at the beginning of the ice age, and potentially to shed light into ancient whale migration patterns.
So, perhaps 2.5 million years ago along this former North Sea shoreline, littered with giant barnacles, the groaning and grunting of humpback whales could have been heard…
References
- What are barnacles? (noaa.gov)
- Reid, J.B., Evans, P.G. and Northridge, S.P. eds., 2003. Atlas of cetacean distribution in north-west European waters. Joint Nature Conservation Committee.
- Buckeridge, J.S., Chan, B.K. and Lin, J.P., 2019. Paleontological studies of whale barnacles in Taiwan reveal new cetacean migration routes in the western Pacific since the Miocene. Zoological Studies, 58.
